Acute renal injury is an important complication of coronavirus disease 2019 (COVID-19). Both COVID-19-specific mechanisms, such as damage to the renal parenchyma by direct infection, and non-specific mechanisms, such as the pre-renal injury factors, have been proposed to be involved in COVID-19-associated renal injuries. In this study, we aimed to elucidate the characteristics of COVID-19-associated renal injuries, focusing mainly on urine sediment findings.
We compared the urine sediment findings and their associations with renal functions or urinary clinical parameters between COVID-19 subjects and non-COVID-19 subjects with acute renal injuries.
We found that the number of urine sediment particles and the levels of N-acetyl-β-D-glucosaminidase, α1-microglobulin, liver type fatty acid-binding protein, and neutrophil gelatinase-associated lipocalin were associated with the severity of COVID-19. In addition, we observed that the number of granular casts, epithelial casts, waxy casts, and urinary chemical marker levels were lower in the COVID-19 subjects than non-COVID-19 subjects with acute renal injuries when the subjects were classified according to their renal function.
These results suggest that pre-renal injury factors might be largely involved in the pathogenesis of COVID-19-associated renal injuries, compared with non-COVID-19-associated renal injuries arising from surgery or sepsis.

Copyright © 2022. Published by Elsevier Ltd.